Recently, with the development of a digital technology, various types of electronic devices such as a mobile communication terminal, Personal Digital Assistant (PDA), an electronic scheduler, a smart phone, a tablet Personal Computer (PC), a wearable device, etc. have been widely used. The electronic device has various functions such as a voice call, message transmission like a Short Message Service (SMS)/Multimedia Message Service (MMS), a video call, electronic organizer, photography, email transmission/reception, broadcast reproduction, Internet, music reproduction, schedule management, Social Networking Service (SNS), messenger, dictionary, game, and the like.
The electronic device uses a battery for portability. The electronic device requires battery charging, and the electronic device performs various functions resulting in an increase in the battery consumption thereof.
In order to reduce battery consumption, the electronic device may separately operate in a general operation mode and a low power operation mode. For example, a low-power operation mode is to save the battery consumption by restricting the use of functions other than must-have functions when the battery's state of charge is very low.
In addition, an electronic device such as a smart watch may operate in an ultra low-power mode by activating only minimum functions (e.g., a clock screen) such as a display and the like. The ultra low-power mode may also be similar to the low-power mode. However, when the ultra-low-power mode is switched to the general operation mode again, there is a problem in that the electronic device is booted from the beginning (e.g., cold booting) similar to a case where the power of the electronic device is switched on. In this case, the electronic device has disadvantages in that it takes a long time to boot up and it becomes an initialized state (e.g., an idle state) rather than being recovered to a conventional state.